A three dimensional image is acquired using respective modalities of an X-ray computed tomography apparatus (hereinafter, referred to as CT (Computed Tomography)), a magnetic resonance imaging apparatus (hereinafter, referred to as MRI (Magnetic Resonance Imaging)), an X-ray diagnostic apparatus, and an ultrasonic diagnostic apparatus. For example, by means of three-dimensional image processing using perspective representation based on a three-dimensional image acquired by CT, a virtual endoscopic image (VE: Virtual Endoscopy) with viewpoints inside tubular bodies such as a digestive tract, tracheae, blood vessels, etc., may be made (for example, Patent Document 1). It should be noted that a modality may be referred to as a medical image diagnostic apparatus. Moreover, a virtual endoscopic image may be referred to as a CT endoscopic image.
Moreover, by using a capsule endoscope passing inside a tubular body such as a digestive tract, tracheae, blood vessels, etc., capsule endoscopic images from viewpoints inside the tube is acquired.
Regarding virtual endoscopic images and capsule endoscopic images, particularly, a three-dimensional medical image processing/displaying apparatus (multi-modality work station) is used for image diagnosis by displaying lesions such as polyps etc. inside gastrointestinal organs such as the large intestine. It should be noted that the three-dimensional medical image processing/displaying apparatus may simply be referred to as a medical image displaying apparatus.
Examination methods of a digestive tract include large intestine analysis (CT colonography) and small intestine analysis (CT Enterography) upon CT, endoscopy, capsule endoscopy, etc.
In large intestine analysis and small intestine analysis upon CT, polyp lesion candidates are examined using virtual endoscopic images. These are not images actually taken inside the digestive tract; therefore, they are not suitable for definitive diagnosis due to reasons such as the inability to observe the actual color of the inner wall, etc.
In endoscopy, an endoscope is directly inserted inside the digestive tract of the patient, and diagnosis of polyp lesions is carried out from images of the inside of the digestive tract taken by a camera at the tip of the endoscope. Although this allows for definitive diagnosis, there is a weak point due to high invasiveness.
In capsule endoscopy, diagnosis of polyp lesions is carried out from images (capsule endoscopic images) inside the digestive tract repeatedly taken when a small (external diameter: approximately 11 mm, length: approximately 26 mm) capsule-shaped endoscope swallowed by the patient passes inside the digestive tract. This is attracting attention as an examination for definitive diagnosis replacing conventional endoscopes due to its low invasiveness.
Low invasive examinations are required with capsule endoscope, so it is thought that a diagnostic workflow for carrying out definitive diagnosis by capsule endoscopy will become mainstream in the future regarding patients in which the lesion candidates have been determined by digestive tract analysis upon CT.